It is known to leak test electric storage batteries prior to shipment. One known technique for such leak testing comprises pressurizing the battery with compressed air through the battery's vent ports followed by measuring the pressure decay over a period of time. If the pressure stays above a specified value, the battery passes. If not, it fails. This technique cannot be used with gas-recombinant-type lead-acid batteries, or other batteries containing a pressure relief check valve in the venting system for maintaining a superambient pressure within the battery and preventing the ingress of ambient air into the battery as the valve prevents pressurization of the battery container.